Home Assistant OS does not support a screeen directly connected to the host machine (even on HDMI), so a remote screen will need to connect over wired or wifi network to the host and a browser or the HA `App` running on another device /OS.

( an alternative option is to run HA supervised on a Linux OS, and use the Linux desktop to display the Browser. This does reduce the number of devices required, but creates more complexity and depedencies on the single host machine running serveral functions.)

I have a standard `tablet` connected in my House HA install, and the battery charging has become an issue over time, so i have chosen to use a dispaly which does not require an internal battery - avoiding standard phone and tablets.

The remote screen will need to automtically bootup into a browser in kiosk mode.

It needs to touchscreen so the controls can be used.

i want to be able to custmomise the screeen brightness in the evening/daytimes.

it needs to fit on the control panel area i have allocated for it.

I have chosen to use a Raspberry Pi  4, with a 10" touch screen (inportrait oerientation ). powered from the existing 5v DC supply. 

Connecting over built-in Wifi to the Vans wireless access point.

• 5v 10A Voltage Regulator
  
  

• Using Raspian Bookworm version, OS with the labwc desktop
  
  

• 10.1" Display from Waveshare.

• 10.1" 12800x800 Touchscreen with DSI
  
  

This needed some Drivers installed from thier Github page, which also includes new screen dimming software.

• https://www.waveshare.com/wiki/10.1inch_DSI_LCD_(C)
  
  

• Setting up Chrome to Launch in Kiosk mode, is quite simple in labwc
  
  
  

• Code on Guthub to be able to control the Raspberry PI touchscreen brightness over mqtt..
  https://github.com/tofuSCHNITZEL/rpi-screenbrightness-mqtt 

The display is registered in mqtt on the HA host and has a simple HA helper setup to automate the screen brightness from 100% daytime, 50% evening, 10% overnight.

• setup a mqtt based RPi system monitoring

https://github.com/ironsheep/RPi-Reporter-MQTT2HA-Daemon#installation

The Waveshare 10" Touchscreen does not come with any bezel and simply mounts with a few screws, the RPi fixes directly to the back.

I made a custom 3d printed bezel to fit the touchscreen, as shown below, with the other controls also in matching style bezels.

I have chosen to use LED RGBWW lighting for the main Habitation area, Kitchen and Bed. Creating 3 seperately controllable zones.

• GIDEALED Smart 2.4G Wireless 5 in 1 WiFi RGBWW LED Controller

Each Zone has a Rotating (Dimmer) Push Switch Control.

• LIGHTEU, Milight Miboxer 2.4G Rotating Switch Panel Remote

The Wifi RGB Controller is a Tuya module, with a BK7231T Chipset. 

This can be reflashed, with a little bit of work using a USB to TTL adapter..

• USB to TTL Adapter
  
  

and allows a much more responsive and locally controllable Wifi LED light controller.  Once setup with MQTT it can be integrated into Home Assistant.

https://openbekeniot.github.io/webapp/devicesList.html

https://github.com/openshwprojects/OpenBK7231T_App/releases

I chose the Atoto S8 Standard replacement HeadUnit.#

Atota S8 Standard DoubleDIN Car Stereo

With an Android OS, it can provide native Android Apps from the Google store, with Google Maps, Chrome Browser etc. 

It also support wireless (or Wired) Apple Carplay and Android Auto to allow a seamless inegration with most mobiles.

It is configured to connect to the Vans local Wifi AP for Internet connectivity.

Loading the Android `Home Assistant` app onto the headunit, allows some device speciifc entities to be exposed into the Van HA system, Media Volume, GPS position (fuel level, car battery level and mileage are there but ive not seen any data yet)

Inspired by another Van tech enthusiast, i built an ESP32-Wroom + MPU6050 Accelerator/Gyro board to provide angle data.

• ESP32-Wroom-Dev board

• MPU-6050 GY-521 Accelerometer Module 3 Axis Gyroscope

I added some enhancements to give me the wheel distance difference - which should help with decisions about how much to raise each wheel to get to level.

And an ajustable `offset` values to help `zero` the van level if the calibration drifts.

I have a PIR Motion Sensor Switch, connected to a 12v computer fan in the shower/toilet cubicle.

This allows the fan to be switched on/off touchfree, with a wave of the hand to help reduce odour or steam/moisture.

• PIR Sensor Switch,Touchless Infrared Switch

I chose to use a Router with the following features

• Wired LAN Ports

just 1 connection required to the HA RPi.

• Wifi AP + DHCP

Broadcast a Wifi AP for the VAN and local devices to connect to.

Allow briding of the Wired and Wifi AP `LAN` to the Internet

• Wifi Client mode

To allow the Router to connect to my home Wifi network whren its within range, or a campsite network if available for internet connectivity.

• 4G Mobile Data (using a physical Sim Card)

For roaming Internet access, 4G is capable enough, (without the need to streaming video or live gaming) using a Lyca Mobile PAYG sim card which can be disabled/enabled remotely when required for travel and has an unlimited Data package option.

• HA integration for view link status, speeds etc.

A few methods could provide this  SNMP, API,MQTT 

I found the Teltonika range of products have a lot of options, and picked yup the RUT241 for a good price , its still in support and can handle my requirements. Pepwave also were considered... but not so available.

• Teltonika RUT241 4G LTE

SNMP turned out to be the simplest option to enable remote monitoring. I have setup around 11 snmp objects to monitor mobile data and Wifi elements in HA.

To get the best reception, of remote Wifi or Mobile Data., an external antenna is required outside of the meal box of a Van. I have the Teltonika external Antenna:

• Teltonika PR1KC640 5G Combo MIMO Mobile Phone/GNSS/WiFi Roof SMA Antenna